Nocturia is a common symptom associated with obstructive sleep apnea. 
WHY? Increases in atrial natriuretic peptide (ANP) is thought to be a possible cause for increased nocturnal urine production amongst OSA patients.
Negative intrathoracic pressure swings caused by obstructive events induces myocardium stretch and the release of ANP. Increased levels of ANP leads to increase sodium and water excretion (natriuresis) and urine production.
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